1. Field of the Invention
The present invention relates to a semiconductor substrate, a manufacturing method of a semiconductor substrate, and a semiconductor device and an electronic device using the semiconductor substrate.
2. Description of the Related Art
In recent years, as an alternative to a single-crystal silicon substrate which is manufactured by thinly slicing an ingot of single-crystal silicon, development of an integrated circuit using a silicon-on-insulator (SOI) substrate has been advanced. An SOI substrate has a structure in which a thin single-crystal silicon layer is provided on an insulating surface. As compared to the case of using a single-crystal silicon substrate, parasitic capacitance between a drain of a transistor and the substrate can be reduced and the performance of the semiconductor integrated circuit can be improved.
There are various manufacturing methods of an SOI substrate, and a method called Smart Cut (registered trademark) is known as a method in which both quality and productivity (throughput) of a formed single-crystal semiconductor layer are balanced. In Smart Cut, hydrogen ions are implanted into a single-crystal silicon substrate (bond wafer) and then the single-crystal silicon substrate is bonded to another substrate (base wafer) at a room temperature. The two substrates are bonded to each other by forming a strong bond utilizing van der Waals force. After that, heat treatment is performed at a temperature of approximately 500° C., so that the single-crystal silicon substrate is separated at a region where hydrogen ions are implanted, and a single-crystal silicon layer is left over another substrate (base wafer).
As an example of a technique of forming a single-crystal silicon thin film over a glass substrate by such Smart Cut, a technique by the present applicant has been known (for example, Patent Document 1: Japanese Published Patent Application No. H11-163363).
In Patent Document 1, an insulating film is formed over a glass substrate, thereby preventing contamination of a single-crystal silicon layer; thus, a semiconductor device having high performance is successfully provided.